"1(0) = - 



gr\'(0) 



1 2 





2 



■m 





+ 



y * 



I «Pi J 



(27) 



l«'(0)| = ^-IV(0)| 



(28) 



|v'(0)| = 



gk , Vu'(0) 



0) O) 



(29) 



where P, is the beach slope at the shoreline and P 2 is the beach curvature at the 

 shoreline. Solutions assume u ' and v ' are bounded and approach for the 

 offshore boundary condition. Howd, Bowen, and Holman (1992) tested the 

 model with analytical solutions using planar and exponential profiles and 

 determined numerical estimates of wave number were accurate to 0.1 percent. 



Oltman-Shay and Howd (1993) compared the Howd, Bown, and Holman 

 (1992) numerical model solutions and the plane-beach analytical solutions with 

 observations from the two NSTS beaches, Torrey Pines and Leadbetter. They 

 found that numerical and analytical estimates of edge wave shoreline variance 

 differed by only 10 to 40 percent (e.g., Table 1). However, they also found that 

 effect of mean longshore current, an asymmetry in the up and downstream k -f 



dispersion curves (e.g., Figure 10), and the effect of a concave steepening of the 

 foreshore in the depth profile, manifesting as a steepening of the dispersion 

 curve from that of a plane beach solution (e.g., Figure 1 1), were observed and 

 well predicted by the numerical solutions using the measured cross-shore 

 profiles of mean alongshore current. 



22 



Chapter 2 Infragravity Wave Dynamics 



